Amazon’s HQ2 could generate millions for Arlington’s affordable housing efforts. Here’s how.

Amazon.com Inc.’s planned Metropolitan Park towers, totaling 2.08 million square feet of office and 67,000 square feet of retail, would exceed the density currently allowed on the Pentagon City site by about 582,000 square feet. And that could mean a huge windfall for affordable housing.

How? This all starts with the previously approved project for the Met Park development site…